Wiktionary
ceruloplasmin
n. (context protein English) A blue metalloprotein that contains copper; it acts as a ferroxidase in association with transferrin
Wikipedia
Ceruloplasmin
Ceruloplasmin (or caeruloplasmin) is a ferroxidase enzyme that in humans is encoded by the CP gene.
Ceruloplasmin is the major copper-carrying protein in the blood, and in addition plays a role in iron metabolism. It was first described in 1948. Another protein, hephaestin, is noted for its homology to ceruloplasmin, and also participates in iron and probably copper metabolism.